Investigation of the process of fluoride ions adsorption by natural sorbents

Abstract

A detailed analysis of literature sources on the content of fluorides in the environment, methods of conditioning and defluoridation of water was held. The mechanism of interaction of fluorides with zeolite in the process of adsorption treatment of wastewaters and domestic waters was clarified. It was first established that in the process of adsorption there is the formation of magnesium fluoride compounds due to the binding of cations extracted from the zeolite by the mechanism of ion exchange. The mechanism of chemisorption of fluoride ions by the formation of insoluble CaF2 was also proved. According to the results of experimental research, a technological scheme has been developed, which provides the preliminary treatment of fluoride ions in the form of complexes with aluminium. In order to prevent the permeation of aluminium fluoride into the treated water, a stage of adsorption water purification was proposed. Calculations of the amount of reagent necessary to ensure the required degree of purification of water from fluoride ions were done. The statistical parameters of the process and the significance of the obtained results were calculated. The coefficient of determination of experimental data was 0.87…0.99, the standard deviation was 0.017…0.026.